﻿<p>This enumeration is used to identify the primary purpose of a duct fitting. This is a very basic categorization mechanism
to generically identify the duct fitting type. Subcategories of duct fittings are not enumerated. </p>
<p class="spec-head">Enumerated Item Definitions:</p> 
	<ul> 
		<li><b>BEND</b>:		A fitting with typically two ports used to change 
        				 		the direction of flow between connected elements.</li>
		<li><b>CONNECTOR</b>:   Connector fitting, typically used to join two
        				        ports together within a flow distribution system 
                                (e.g., a coupling used to join two duct segments).</li>
		<li><b>ENTRY</b>:       Entry fitting, typically unconnected at one port
        				        and connected to a flow distribution system at 
                                the other (e.g., an outside air duct system 
                                intake opening).</li>
		<li><b>EXIT</b>:        Exit fitting, typically unconnected at one port
        				        and connected to a flow distribution system at 
                                the other (e.g., an exhaust air discharge 
                                opening).</li>
		<li><b>JUNCTION</b>:	A fitting with typically more than two ports used
        				        to redistribute flow among the ports and/or to
                                change the direction of flow between connected
                                elements (e.g, tee, cross, wye, etc.).</li>
		<li><b>OBSTRUCTION</b>: A fitting with typically two ports used to 
        				        obstruct or restrict flow between the connected
                                elements (e.g., screen, perforated plate, etc.).</li>
		<li><b>TRANSITION</b>:	A fitting with typically two ports having
        				        different shapes or sizes. Can also be used to
                                change the direction of flow between connected
                                elements.</li>
		<li><b>USERDEFINED</b>: User-defined fitting.</li>
		<li><b>NOTDEFINED</b>:  Undefined fitting.</li>
	</ul> 
    
	<blockquote class="history">HISTORY&nbsp; New enumeration in IFC2x2.</blockquote>
